1. Field of the Invention
This invention relates generally to the lubricating and conditioning of textile fibers, filaments, and yarns. It relates particularly to an aqueous solution or dispersion for melt spun yarns comprising a single synthetic organic component which is heat stable, light stable, chemically stable, and bio-degradable.
2. Prior Art
Finishes are universally applied to fiber surfaces to improve the subsequent handling and processing of the fibers. The composition and amount of finish applied depend in large measure upon the nature -- i.e., chemical composition -- of the fiber, the particular stage in the processsing of the fiber, and the end use in view.
For example, spin finishes are applied to melt-spun filaments to lubricate them before the winding thereof as yarns on a spin bobbin, and to prevent balooning apart of the individual filaments because of the electrostatic charges which accumulate on their surfaces in the spinning processes. Such spin finishes also provide a slight cohesion between the individual filaments of a yarn thereby aiding in the prevention of damage during the winding and unwinding of the yarn.
The application of spin finish is generally accomplished by contacting the solidified filaments with a solution, or more commonly, an organic-water emulsion, containing at least a lubricant and an antistatic agent. Wetting agents, as well as emulsifiers and viscosity stabilizers, are also commonly found in spin finish emulsions. Ordinarily, a wick, or a roller rotating in a bath of the finish, is employed to apply the finish to the filament surfaces.
Except for equilibrium amounts, all water is subsequently removed from the surface of the treated yarn -- for example, as a result of the heat generated in drawing and other yarn processing operations, or by evaporation in storage.
Acceptable spin finishes must fulfill a number of requirements in addition to providing the desired lubricating and antistatic effects. For example, they should be easy to apply (and to remove if desired), they should have good light stability, thermal stability, and chemical stability, and they should not adversely affect the physical or chemical properties of the filaments to which they are applied or subsequent processes to which the treated filaments are subjected.
Of the many compositions which have been proposed as finishes, especially spin finishes for melt spun filament yarns, some of the more noteworthy are found in the following U.S. Pat. Nos. 3,649,535; 3,428,560; 2,803,565; 3,306,850; 3,850,819; 3,652,419; 3,781,202; 3,056,744; 2,853,453; 2,842,462; 3,814,627; 3,446,734; 3,113,369; 3,639,154; and 2,677,700. Notwithstanding the efficacy of these and similar compositions, all consist of a plurality of essential organic components in addition to water, and as a result, many require the presence of an emulsifier or emulsification system as well. Moreover, in certain applications, as exemplified by the standard space dyeing procedures for polyamide yarns, spin finishes are not removed from the yarns to which they were applied. That is to say, after being stored for varying lengths of time, polyamide yarns to be space dyed are subjected to various treatments which, because of the action of heat and/or light and/or chemicals, unfortunately result in an undesirable yellowing of virtually all of the spin finishes heretofore employed. Ordinarily such yellowing in turn adversely affects both shade and clarity of the space dyed product. Furthermore, in applications wherein spin finishes must be removed (e.g., by scouring with water either before or after certain yarn processing steps), ecological problems are generally inherent in the final disposal of effluents.